1. Field of Invention
This invention is directed to contact transfer of liquid toner images.
2. Description of Related Art
Efficient contact transfer of a toner image from a first substrate to a second substrate without the assistance of an electrostatic field or heat has not yet been possible using conventional printers or inks. Efficient contact transfer requires that the toner image must adhere better to the second substrate than to the first substrate and the toner image must also be cohesive enough to prevent distortion of the image. However, conventional liquid toners do not have the material properties necessary to meet these requirements because other subsystems such as development, cleaning and replenishment systems require toners with conflicting material properties.
This invention provides methods and systems that efficiently transfer liquid toner images using an absorbent coating under the toner image. The absorbent coating absorbs carrier fluid from the toner image. The absorption of the carrier fluid increases the solid content of the toner image. When a phased-film-forming ink is used, the removal of fluid increases the cohesiveness of the toner image and makes the toner image ready to be transferred at ambient temperature with simple pressure contact.
The systems and methods of the invention include developing a latent image with a phased-film-forming ink or self-fixing ink and conditioning the ink by absorbing carrier fluid from the ink using an absorbent coating over an image bearing member. Conditioning the image using an absorbent coating increases the developed image""s internal cohesion and/or makes the developed image sufficiently adhesive by increasing the solid content of the ink. The ink image quickly reaches a high solid content due to the loss of carrier fluid to the absorbing substrate. This conditioned image is suitable for contact transfer.
Additionally, the carrier fluid in the absorbent coating can be released during the transfer and may serve as a release layer for releasing the developed image from the image bearing member.
The methods and systems of this invention do not require additional image conditioning to provide a highly efficient transfer. Additionally, the systems and methods of this invention enable an image with a very high solid content to be transferred and provide a very high quality transfer that is comparable to conventional transfix methods but at a much lower temperature. Additionally, the systems and methods of this invention have a large latitude for process control, such as the solid content, the process pressure, the process temperature and the like.
While the methods and systems of this invention may benefit from an electrostatic method and/or system to assist in the transfer of the toner image, the methods and systems of this invention provide for more effective toner image transfer with electrostatic voltages and are equivalent or lower than that typically provided for conventional electrostatic transfer processes.
These and other features and advantages are described in or are apparent from the following detailed description of the preferred embodiments.